Pneumatic devices having cascaded sets



DCC- 15, 1964 J. E. FLEcKENsrI-:IN 3,151,025

PNEUMATIC DEVICES HAVING CASCADED SETS OF CONCENTRIC ORIFIGES Filed Oct. 30, 1961 INVENTOR E/f JOSEPH e. FLECKENsTrN ATTORNEYS.

United States Patent Ofi-ice PNEUlVfATIC DEVICES HAVWG CASCADED SETS F CONCENTRIC ORIFICES Joseph E. Fleckenstein, Milwaukee, Wis., assigner to Johnson Service Company, Milwaukee, Wis., a corporation of Wisconsin Filed Oct. 30, 1961, Ser. No. 148,321 8 Claims. (Cl. 6th-60) This invention relates to'improvements in pneumatic devices having cascaded sets of concentric orifices.

In my Ico-pending application, Serial No. 148,127, filed 'October 27, v1961, now abandoned, there is disclosed a pneumatic device lhaving a single set of concentric orifices. With the design 'of the co-pending application, using a Supply pressure in the proximity of 5 to 10 inches of 'water and a high pressure orifice diameter in the proximity of .010 to .020 inch, itis possible to obtain a vacuum in the intermediate chamber which has a value equal to as much as 77% of the absolute value of the supply pressure. There are applications, however, where it is desirable, with a given supply pressure, to obtain still higher vacuums. Such higher vacuums are particularly useful in providing a simple control for devices 'such as dampers, valves, or the like.

In the heating and Ventilating industry there has been a recent trend to use controls which operate from the pressure of the controlled medium. Difficulties, however, have been encountered in those applications which utilize a medium at a relatively low pressure where it is desired to use said pressure to operate dampers. For example, in units which control the flow of air, it is de- 'sirable to use the pressure of the air to operate the dampers. Normally, the value of the air pressure delivered to a unit of this type would not be in excess of approximately 5 to 10 inches of Water, which is cornparably low. Higher fluid pressure differences would be desirable. so as to permit the design of damper operators or other devices which are not ltoo large in size, but which have sufiicient force to overcome the resisting forces of friction and the forces introduced by throttling streams of 'air which havecomparably high pressures and velocity. z Y v It is a general object of the present invention to provide a novelarrangement` comprising cascaded sets of concentric orificesvwhich are designed and arranged to improve selfacontained unit ventilator designs for the like by increasing the pressure difference available at the unit. `A further object of the invention is to provide a device, as above described, which is relatively c ompact, foolproof andy -well adapted for the purpose described.

With theabove and other objects in View, the inveny.

tion consists of theimproved pneumatic device having cascaded sets of concentric orifices, and all of its parts and combinations, as set forth in the claims, and all equivalents thereof. y v

In the accompanying drawings, illustrating one complete embodiment of the preferred form of the invention, in which the same reference numerals designate the same parts in all of the views: K

FIG'. 1 is a longitudinal sectional View, partially diagrammatic, showing the cascaded sets of concentric orifices in exaggerated size as used in conjunction with an operator for a device such as a damper for a unit ventilator, a valve, or the like;

FIG. 2 is a plan view of the high pressure orifice plate `of the first set of concentric orifices.

FIG. 6 is a plan view of the spacer for the second set;

FIG. 7 is `a plan View of the low pressure orifice plate for the second set; and

FIG. 8 is a fragmentary sectional view showing a Way of controlling the supply pressure for an `operator such as a damper operator.

Referring more particularly to the drawing, the numeral 10 de-signates a supply pressure inlet, which may extend from a suitable source of low pressure air, which may be the pressure of the controlled medium in a heating or Ventilating system. The first `concentric orifice unit, or set of concentric orifices 9, includes a disk or plate 11 having a high pressure orifice 12 in the center thereof. There 'is also a disk or plate 13 having a low pressure orifice 14 in the center thereof which is aligned with and larger than the orifice 12. The disks 11 and 13 are separated by a spacer disk or plate 15 having a relatively large central opening forming an intermediate chamber 16. The latter chamber is much larger than the orifices 12 and 14, as is clear from FIG. l. A radial duct 17 is in communication with the intermediate chamber 16 and is adapted to be connected through a conduit 18 with a desired pneumatic device'. In the exemplification of FIG. l the duct 1S is connected with the vacuum'chamber 19 of an operator 26, such as an op- ,lerator used in connection with 'a damper for a unit ventiator.

The 'latter operator may comprise a -diaphragm 21,

suitably supported for diaphragm movement, in a charnber 22 of a suitable housing. The diaphragm is adapted to be acted upon in one direction by atmospheric pressure or by pressure from a duct 23 connected with a suitable source of pressure, such as the pressure of the controlled medium. By use of mechanism as shown in FIG. 8, there is a source of supply pressure 41 which may lead from the controlled medium. This supply pressure iiows through a restricting port 42 and its exhaust is controlled by the lid 40. This lid movement may be `controlled lthermostatically or in any suitable manner. When the lid 4G is in a position to restrict exhaust from the conduitportion 43, pressure builds up therein and is increased in the take-off line 44. In the form of the invention of FIG. l, the take-ofi line may connect with the port 23 to control the pressure therein. The pressure in chamber 30 acts against a spring 24 on the other side of the damper, but is aided by the vacuum in the chamber 19. Movement of the damper actuates a rod 25 which extends through a suitable seal 26 and which is adapted to be connected to a damper 0r other'instru` ment to be moved (not shown). l

The exhaust from the first set 9 of concentric orifices is in communication, through a conduit portion'27, with a second set of concentric orifices, said second set being designated generally by the numeral 28 and being arranged for convenience at right angles to the first set and also having larger dimensional values throughout. The set of concentric orifices 28 includes a disk or plate 29 having a high pressure orifice 30 in the center thereof. There is also a disk or plate 31, having a low pressure orifice 32 in the center thereof, which is aligned with andlarger than the orifice 30. The disks 29 and 31 are separated by a spacer disk or plate 33, having a relatively large central opening, forming an intermediate chamber 34. The latter chamber is much larger than the orifices 30 and 32, as is clear from FIG. l. A radial duct 35 is in'communication with the conduit portion 27 leading Y from the exhaust of the first set of concentric orifices.

Supply pressure, which is preferably the same as the pressure in the inlet 1t), is supplied to the second set of concentric orifices by an inlet 36, and the exhaust from y the second set of concentric orices flows out through Patented Dec. 15, 1964 a suitable outlet 37 under control of a suitably actuated lid 37. The lid movement may be controlled thermostatically or in any other suitable manner.

If the diaphragm 21 of FIG. l had no vacuum acting in the chamber 19, and if atmospheric pressure (in addition to the spring 24) were acting on the upper side of the diaphragm 21, and if the air pressure delivered through the duct 23 were only the comparably'low value which is usually available in the air being controlled, which would be approximately 5 to 10 inches of water, it would not have sufficient force to operate certain larger dainpers and to overcome the resisting forces of friction and the forces introduced by throttling streams of air, which latter have comparatively high pressures and velocitics. With the arrangement just described, where atmospheric pressure would be acting on the upper side of the diaphragm 21, and with a supply pressure of 6 inches of water, with the high pressure orifice 12 having a diameter of .O14 inch, with the spacer 15 having a thickness of .040 inch, and with a low pressure orifice diameter at 14 of .020 inch, a vacuum of 3.81 inch of water may be obtained. This vacuum has a value of 63.5% of the absolute value of the supply pressure, and with a single set of concentric orifices, such as the left-hand set of FIG. l, the maximum value which can be obtained is approximately 77% of the absolute value of the supply pressure.

The present arrangement of cascaded sets of concentric orifices is, therefore, a novel arrangement for increasing the pressure difference available at the unit to a sufficient extent to permit the operation of relatively large dampers by using the same pressure difference available at the unit; that is, a relatively low air pressure of approximately 5 to l0 inches of water. For the same pressure change the force acting on the rod 25 can be considerably increased by decreasing the pressure in the chamber 19 by any suitable means, such as through moving the lid 37' away from closing position. At the same time the pressure is proportionately increased in the chamber 30 by any suitable means, such as by moving the lid 40 (FIG. 8) toward closing position.

With the cascaded sets of concentric orifices of VFIG. 1, a vacuum can be produced at 16 which may be used in the operator chamber 19 and which is well over 100% of the absolute value of the supply pressure. With this arrangement, the force exerted by the stem 25, which may be used to operate a damper or the like, can be substantially increased.

Another possible arrangement, which would require two sets of cascaded concentric orifices, would require the connection of the conduit 18 of FIG. 1 to one chamber, such as the chamber 19 of an operator, and the connection of the corresponding conduit from another set of cascaded concentric orifices to the duct 23 to act in the other chamber 30 of said operator. In such an arrangement the pressure in one chamber, such as the chamber 19, could be progressively increased by use of the control lid 37 to a positive pressure in said chamber 19 and, at the same time, a reverse action could be taking place in the chamber 30 through reverse operation of the lid 37 of the other set of cascaded concentric orifices.

In the arrangement of FIG. 1 it is preferred that the first set of concentric orifices have a high pressure orifice diameter in the proximity of .010 to .020 inch of water, with the supply pressure in the proximity of 5 to l0 inches of water, the thickness of the spacer being approximately 2 to 5 times the diameter of the hole 12, and the diameter of the hole 14 being approximately 1.5 times the diameter of the hole 12. In the second set 28 of concentric orifices the diameter of the high pressure orifice 30 is preferably at least 3 times the diameter of the corresponding hole 12 of the first set 9 and the supply pressure in 36 is preferably equal to the supply pressure in 10.k

The diameter of the orifice 32 of the second set is preferably approximately l.5 times the diameter of the orifice 30, and the thickness of the spacer 33 is preferably approximately 2 to 5 times the diameter of the hole 30. In one experiment it was possible to obtain a vacuum at 16 equal to 102% of the absolute value of the supply pressure when the orifice 12 was .020 inch and the orifice 30 was .063 inch.

Various changes and modifications may be made without departing from the spirit of the invention, and all such changes may be contemplated as may come within the scope of the claims.

What I claim is:

1. A vacuum producing device comprising. a first cond centric orifice unithaving a first plate with a relatively small high pressure orifice of .010 to .020 inch in diameter and having a second plate spaced therefrom with a low pressure orifice which is approximately 1.5 times larger than said high pressure orifice aligned with the latter, and there being an intermediate chamber in communication with both orifices which is of substantially larger size than said orifices with a vacuum duct leading therefrom which is connectable with a device to be controlled; an inlet conduit connectable with a relatively low pressure source of fluid leading to said high pressure orifice; second concentric orifice unit like said first unit but have ing a high pressure orifice approximately 3 times the diam eter of the high pressure orifice of said first unit and havJ ing a low pressure orifice and an intermediate chamber of respectively larger size; means for conducting the exhaust from the low pressure orifice of the first unit to the' intermediate chamber of the second unit; a' relatively low pressure source of fluid in communication with the high pressure orifice of the second unit; and means for' exhaust-l ing fiuid from the low pressure orifice of said second finit,

2. A vacuum producing device comprising: a first coriq centric orifice unit including a first plate having a relatively small high pressure orifice, including a second plate having a low pressure orifice which is larger than said high pressure orifice aligned with the latter, and including spacer means between said plates having an intermediate chamber in communication with both orifices which is of substantially larger size than said orifices, there being a vacuum duct leading from said intermediate chamber which is connectable With a device to be controlled; an inlet conduit connectable with a source of pressure and leading to said high pressure orifice; a second concentric orifice unit including a first plate having a high pressure orifice which is larger than the high pressure orifice of the first unit, including a second plate having a low pressure orifice which is larger than the low pressure orifice of the first unit aligned with the high pressure orifice of said second unit, and including a spacer between said plates having an intermediate chamber in communication with both orifices, said spacer being of greater thickness than the spacer of the first unit; means for conducting the exhaust from the low pressure orifice of said first unit to the intermediate chamber of said second unit; a source for fluid under pressure in connection with the high pressure orifice of the second unit; and conduit means for leading exhaust uid away from the low pres' sure orifice of said second unit.

3. A vacuum producing device comprising: a first concentric orifice unit including a first plate having a relatively small high pressure orifice of .010 to .020 inch in diameter, including a second plate having a low pressure orifice which is approximately 1.5v times larger than said high pressure orifice aligned with the latter, and including a spacer means between said plates which has a thickness 2 to 5 times the diameter of the high pressure orifice to provide an intermediate chamber in communication with both orifices which is of substantially Ilarger size than said orifices, there being a vacuum duct leading from said intermediate chamber which is connectable with a device to be controlled; an inlet conduit connectable with a relatively low pressure source of fiuid and leading to said high pressure orifice; a secild concentric OC@ u'nit including a first plate having a high pressure orifice which is approximately 3 times the diameter of the high pressure orifice of the first unit, including a second plate having a low pressure orifice which is approximately 1.5 times larger than the high pressure orifice of the second unit aligned with the high pressure orifice of said second unit, and including a spacer between said plates which has a thickness 2 to 5 times the diameter of the high pressure orifice of the second unit to provide an intermediate chamber in communication with both orifices; means for conducting the exhaust from the low pressure orifice of said first unit to the intermediate chamber of said second unit; a relatively low pressure source for fluid in connection with the high pressure orifice of the second unit; and conduit means for leading exhaust fluid away from the low pressure orifice of said second unit.

4. A vacuum producing device comprising: a first concentric orifice unit including a first plate having a relatively small high pressure orifice of .010 to .O20 inch in diameter, including a second plate having a low pressure orifice which is approximately 1.5 times larger than said high pressure orifice aligned with the latter, and including a spacer means between said plates which has a thickness 2 to 5 times the diameter of the high pressure orifice to provide an intermediate chamber in communication with both orifices which is of substantially larger size than said orifices, there being a vacuum duct leading from said intermediate chamber which is connectable with a device to be controlled; an inlet conduit connectable with a relatively low pressure source of fluid and leading to said high pressure orifice; a second concentric orifice unit including a first plate having a high pressure orifice which is approximately 3 times the diameter of the high pressure orifice of the first unit, including a second plate having a low pressure orifice which is approximately 1.5 times larger than the high pressure orifice of the second unit aligned with the high pressure orifice of said second unit, and including a spacer between said plates which has a thickness 2 to 5 times the diameter of the high presslne orifice of the second unit to provide an intermediate chamber in communication with both orifices; means for conducting the exhaust from the low pressure orifice of said first unit to the intermediate chamber of said second unit; a relatively low pressure source for fluid in connection with the high pressure orice of the second unit; conduit means for leading exhaust fluid away from the low pressure orifice of said second unit; and means for controlling said exhaust.

5. An operating device for a damper or the like comprising: a housing having a cavity, a diaphragm transversing said cavity to provide a first fluid chamber on one side of said diaphragm and a second fluid chamber for its other side; means for supplying relatively low pressure fluid to said first chamber to urge said diaphragm in one direction; spring means acting on the other side of said diaphragm to urge it in the opposite direction; motion transmitting means connected to said diaphragm; and means for creating a vacuum in said second fluid chamber to increasey the force change of said motion transmitting means for a given fluid pressure change in said first chamber, said vacuum creating means including: a first concentric orifice unit having a first plate with a relatively small high pressure orifice and having a second plate spaced therefrom with a low pressure orifice which is larger than said high pressure orifice aligned with the latter and there being an intermediate chamber in communication with both orifices which is of substantially larger size than said orifices with a vacuum duct leading therefrom which is connected with said second fluid chamber; an inlet conduit connectable with a relatively low pressure source of fluid leading to said high pressure orifice; a second concentric orifice unit like said first unit but having high and low pressure orifices and an intermediate chamber of respectively larger size, means for conducting the exhaust from the low pressure orifice of sure orifice of said second unit.

6. An operating device for a damper or the like comprising: a housing having a cavity, a diaphragm transversing said cavity to provide a first fluid chamber on one side of said diaphragm and a second fluid chamber for its other side; controlled means for supplying relatively'low pressure fluid to said first chamber to urge said diaphragm in one direction; spring means acting on the other side of said diaphragm to urge it in the opposite direction, motion transmitting means connected to said diaphragm; and means for creating a Vaculnn in said second fluid chamber to increase the force change of said motion transmitting means for a given fluid pressure change in said first chamber, said vacuum creating means including: a first concentric orifice unit having a first plate with a relatively small high pressure orifice and having a second plate spaced therefrom with a low pressure orifice which is larger than said high pressure orifice aligned with the latter and there being an intermediate chamber in communication with both orifices which is of substantially larger size than said orifices with a vacuum duct leading therefrom which is connected with said second fluid chamber; an inlet conduit connectable with a relatively low pressure source of fluid leading to said high pressure orifice; a second concentric orifice unit like said first unit but having high and low pressure orifices and an intermediate chamber of respectively larger size, means for conducting the exhaust from the low pressure orifice of the first unit to the intermediate chamber of the second unit; a relatively low pressure source of fluid in communication with the high pressure orifice of the second unit; means for exhausting fluid from the low pressure orifice of said second unit; and means for controlling said lastmentioned exhaust.

7. An operating device for a damper or the like comprising: a housing having a cavity, a diaphragm transversing said cavity to provide a first fluid chamber on one side of said diaphragm and a second fluid chamber for its other side; controlled means for supplying fluid mitting means for a given fluid pressure change in saidv first chamber, at least one of said fluid sources being a vacuum; and means for creating said vacuum, including: a first concentric orifice unit having a first plate with a relatively small high pressure orifice and'having a second plate spaced therefrom with a low pressure orifice which is larger than said high pressure orifice aligned with the latter and there being an intermediate chamber in communication with both orifices which is of substantially larger size than said orifices with a vacuum duct leading therefrom which is connected with one of said chambers of the operating device; an inlet conduit connectable with a source of pressure fluid leading to said high pressure orifice; a second concentric orifice unit like said first unit but having high and low pressure orifices and an intermediate chamber of respectively larger size, means for conducting the exhaust from the low pressure orifice of the first unit to the intermediate chamber of the second unit; a source of fluid under pressure in communication with the high pressure orifice of the second unit; means for exhausting fluid from the low pressure orifice of said second unit; and means for controlling said last-mentioned exhaust.

8. An operating device for a damper or the like comprising: a housing having a cavity, a diaphragm transversing said cavity to provide a first fluid chamber on one side of said diaphragm and a second fluid chamber for its other side; means for supplying relatively 10W pressure iiuid to said first chamber to urge said diaphragm in one direction; spring means acting on the other side of said diaphragm to urge it in the opposite direction; motion transmitting means connected to said diaphragm; and means for creating a vacuum in said second fluid chamber to increase the force change of said motion transmitting means for a given fluid pressure change in said rst chamber, said vacuum creating means including: a concentric orifice unit having a iirst plate with a relatively small high pressure oriice and having a second plate spaced therefrom with a low pressure orifice which is larger than said high pressure orifice aligned with the latter and there being an intermediate chamber in communication with both orifices which is of substantially References Cited in the le of this patent UNITED STATES PATENTS 500,677 Stanley July 4, 1893 1,025,504 Birrell May 7, 1912 2,095,833 Rockwell Oct. 12, 1937 Y FOREIGN PATENTS 450,209 Great Britain July 13, 1936 

1. A VACUUM PRODUCING DEVICE COMPRISING: A FIRST CONCENTRIC ORIFICE UNIT HAVING A FIRST PLATE WITH A RELATIVELY SMALL HIGH PRESSURE ORIFICE OF .010 TO .020 INCH IN DIAMETER AND HAVING A SECOND PLATE SPACED THEREFROM WITH A LOW PRESSURE ORIFICE WHICH IS APPROXIMATELY 1.5 TIMES LARGER THAN SAID HIGH PRESSURE ORIFICE ALIGNED WITH THE LATTER, AND THERE BEING AN INTERMEDIATE CHAMBER IN COMMUNICATION WITH BOTH ORIFICES WHICH IS OF SUBSTANTIALLY LARGER SIZE THAN SAID ORIFICES WITH A VACUUM DUCT LEADING THEREFROM WHICH IS CONNECTABLE WITH A DEVICE TO BE CONTROLLED; AN INLET CONDUIT CONNECTABLE WITH A RELATIVELY LOW PRESSURE SOURCE OF FLUID LEADING TO SAID HIGH PRESSURE ORIFICE; A SECOND CONCENTRIC ORIFICE UNIT LIKE SAID FIRST UNIT BUT HAVING A HIGH PRESSURE ORIFICE APPROXIMATELY 3 TIMES THE DIAMETER OF THE HIGH PRESSURE ORIFICE OF SAID FIRST UNIT AND HAVING A LOW PRESSURE ORIFICE AND AN INTERMEDIATE CHAMBER OF RESPECTIVELY LARGER SIZE; MEANS FOR CONDUCTING THE EXHAUST FROM THE LOW PRESSURE ORIFICE OF THE FIRST UNIT TO THE INTERMEDIATE CHAMBER OF THE SECOND UNIT; A RELATIVELY LOW PRESSURE SOURCE OF FLUID IN COMMUNICATION WITH THE HIGH PRESSURE ORIFICE OF THE SECOND UNIT; AND MEANS FOR EXHAUSTING FLUID FROM THE LOW PRESSURE ORIFICE OF SAID SECOND UNIT. 